Since version 102.2 of the game, the way to build underwater tunnels has changed, because Underground slope was implemented. After several attempts (with multiple failures
) and reading some post on the forum about how works the new underground slopes, I wrote this tutorial - how to build underwater tunnels.
1) Choose the
'vertically raise/lower land' tool, select the
'lower square' tool, and
dig a pit of 2 squares length on each side of the land.
2) From the tool 'vertically raise/lower land' select the 'raise square' tool and create a slope on each tile on both sides of the ocean.
3) From the 'vertically raise/lower land' tool select the vertical artificial slope tool,
build two artificial slopes and lay the road (or railroad) as shown in the picture.
4) From the 'Road tool' select the
'Road tunnel' tool and then
press Ctrl + click on the artificial slope for the tunnel entrance (only the tunnel entry is built, not the whole tunnel). Repeat on the other tunnel entrance.
5) Open the
'Game Options' (diskette icon), select
'Display', then check
'sliced underground mode' and clicking on the tiny arrows choose the value -2
In the underground view can be seen
the entrance of each section of the tunnel at water level.
6) Now we
push down the road 1 level, so
the tunnel will pass under the water. From the
'vertically raise/lower land' tool select the 'lower artificial slope' tool and click at the road-end of each section of tunnel. As a result we have sent the road one level below.
The road was lowered 1 level underground
7) In the 'sliced underground mode'
click on the arrow and set the underground level to -3. You can see the
2 sections of road that we have sent one level down.
Select the 'Road tunnel' tool, then click on the start tile, then the end and a tunnel will be built between these points. Uncheck 'sliced underground mode'.
8.) From the tool 'vertically raise/lower land' select the 'Restore natural slope' tool and
remove the artificial slopes built in 2)
The tunnel finished:
